gistfile1.txt

<?php

$controllerObjectName = 'F3\Foo\Bla\Controller\Abc\Xyz\QuuxController';
$controllerObjectName = 'F3\Foo\Service\Rest\V1\QuuxController';
$matches = array();
		preg_match('/
			^F3
			\\\\(?P<packageKey>[^\\\\]+)
			(
				\\\\Controller
			|
				\\\\(?P<subpackageKey>.+)\\\\Controller
			|
			)
			\\\\(?P<controllerName>[a-z0-9\\\\]+)Controller
			$/ix', $controllerObjectName, $matches
		);

		var_dump($matches);

?>

modifications:

• moved the \ before "Controller" into the submatch
• added 0-9 to the ControllerName
• added empty alternative as LAST altrnative (order is important here)